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Time Calculator

Add and subtract hours, minutes and seconds.

How to use Time Calculator

  1. Choose whether you want to add/subtract two durations, or find the difference between two times of day.
  2. In Add/Subtract mode enter hours, minutes and seconds for Time A and Time B, then pick + or −.
  3. In Difference mode pick the start time and end time and read the interval.

About Time Calculator

Working with hours, minutes and seconds by hand is error-prone because there are 60 seconds in a minute and 60 minutes in an hour, not 100. This tool carries over values correctly so you can sum timesheets, plan journeys or measure laps.

All inputs are interpreted as durations or clock values, not dates. For date arithmetic use the Date Calculator.

Features

  • Add and subtract durations with hours/minutes/seconds
  • Time-difference mode between two clock values
  • Total in seconds alongside the h/m/s breakup
  • Works with any currency/unit (pure numbers)

Frequently asked questions

Can the result be negative?

Yes, in Add/Subtract mode. A negative value means you subtracted more than you started with, displayed with minus signs.

What if the end time is before the start time across midnight?

This simple calculator works inside a single 24-hour period. Use the Date Calculator together with this tool when spans cross days.

Does it handle decimals?

Each field accepts whole numbers. To enter a fraction convert it to the smaller unit: 1.5 hours = 1 hour 30 minutes.

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